I have bee using FDS-CDU for some years now without any hick ups, I went for a flight the night before last and all went well just like the last 32 flights on the trip I'm doing. I went for one tonight and my Capt FDS-CDU stopped working some of the buttons like all the buttons from clear and above to E and a couple more like the Ident button.
Any suggestions on what may have gone wrong? F/O goes sweet as.